#! /bin/bash
#
# get a memory profile flamegraph of a kit session
# 1. to start memory profiling
# scripts/memoryprofile-cool <PID> start
# 2. to explicitly dump a memory profile
# scripts/memoryprofile-cool <PID> dump
# 3. to stop memory profiling
# scripts/memoryprofile-cool <PID> stop
# 4) to generate memory flamegraph
# scripts/memoryprofile-cool <PID> visualize

# Typical use is to identify the spare kit that will be used and start
# profiling from that ready-to-use point. e.g. Open and close a document to
# prime a local debug setup to create initial subforkit and then pstree -plt
# `pidof coolwsd` to get the pid of the kit_spare_XXX process that is a child
# of the "subforkit_XXX" process and: scripts/memoryprofile-cool <PID> start,
# etc.
#
# Don't close the document until after visualize is complete because pprof
# needs the proc/<PID>/maps info and tcmalloc is unable to automatically
# provide that in the kit chroot environment so this script fixes the profile
# up for use by pprof.

if ! which flamegraph.pl > /dev/null 2>&1; then
    REAL_USER_HOME="$(getent passwd $SUDO_USER | cut -d: -f6)"
    PATH=$PATH:$HOME/FlameGraph:$REAL_USER_HOME/FlameGraph
fi
if ! which flamegraph.pl > /dev/null 2>&1; then
    echo "no flamegraph.pl found"
    echo "On fedora install systemwide with: sudo dnf install flamegraph"
    echo "Otherwise install locally manually into ~/FlameGraph"
    echo "    e.g. git clone https://github.com/brendangregg/FlameGraph ~/FlameGraph"
    exit 1
fi

if [ -z "$2" ]
then
    echo 'error: Usage: memoryprofile-cool <PID> start|dump|stop|visualize' >&2
    exit 1
fi

PPROF=pprof
# debian/ubuntu use google-pprof as the name, pprof was taken by tau package already
if grep -q "ID_LIKE=debian" /etc/os-release; then
    PPROF=google-pprof
fi

case $2 in
start)
    gdb --pid $1 -batch -iex "set sysroot /" -ex='call (void)HeapProfilerStart("/tmp/kitheap-'$1'")'
    ;;
dump)
    gdb --pid $1 -batch -iex "set sysroot /" -ex='call (void)HeapProfilerDump("explicit")'
    ;;
stop)
    gdb --pid $1 -batch -iex "set sysroot /" -ex='call (void)HeapProfilerStop()'
    ;;
visualize)
    LATEST=`ls -t jails/*/tmp/cool-*/kitheap-*.*.heap|head -n 1`
    if [ `tail -1 $LATEST` = "MAPPED_LIBRARIES:" ]; then
        echo "recovering missing MAPPED_LIBRARIES"
	cat /proc/$1/maps >> $LATEST
    fi
    $PPROF --collapsed ./coolforkit-ns $LATEST | flamegraph.pl --color=mem > kitheap-$1.svg
    ;;
*)
    echo "unknown command: " $2
    ;;
esac